How do you calculate stacker capacity for a drywall line?

Multiply boards per stack by stacks per shift to get gross output, then multiply by stacker uptime and quality yield. With 4 boards/stack, 480 stacks/shift, 90% uptime and 97% yield you get 1,920 gross dropping to 1,676 good boards.

What is the difference between gross and good stacker capacity?

Gross capacity (1,920 boards in the example) is the theoretical count if the stacker never stopped and every board passed. Good capacity (1,676) is what survives after 192 boards of uptime loss and 51.8 boards of yield loss.

What is a good stacker uptime for gypsum board?

Well-run board lines target 92-96% stacker uptime; the 90% default here already costs 192 boards per shift. Below ~88% the stacker usually becomes the line constraint.

Why does a small yield drop matter on a stacker?

Each rejected board is fully loaded with stucco, paper and dryer fuel, so the 3% yield gap costing ~52 boards per shift represents finished product value scrapped, not just lost machine time.

How do I increase good output without speeding up the stacker?

Recover uptime and yield first. Closing the 90% uptime to 95% adds roughly 95 boards per shift here, often cheaper than chasing a faster cycle that the dryer can't feed.

Stacker capacity vs dryer capacity, which sets the line rate?

Whichever is lower governs. Run this calculator against your dryer's good-board rate; if stacker good output sits below dryer output, the stacker is your bottleneck.

Gypsum, Drywall & Interior Panel Manufacturing calculator

Stacker Capacity Calculator

Stacker Capacity tells a gypsum board plant how many sellable boards the automatic stacker can actually deliver per shift after downtime and quality losses are subtracted from the raw throughput. Line supervisors, production planners, and continuous-improvement engineers use it to size daily commitments, spot the stacker as a bottleneck behind the dryer, and reconcile rated capacity against what the warehouse really receives. On a high-speed board line the stacker is the last machine before the lumber yard, so its effective rate caps the whole line. Knowing the gap between gross and good output turns vague 'the stacker is slow' complaints into a number you can act on.

What this calculator does

Estimate end-of-line stacker output for a shift by combining boards per stack, stacks per shift, stacker uptime, and quality yield.
Use it when the board line is increasing speed and you need to confirm the stacker can keep pace without creating a backlog at the end of the dryer.
It computes good boards delivered per shift by multiplying boards per stack and stacks per shift, then derating that gross figure by stacker uptime and quality yield.

Formula used

Gross stacker output = boards per stack x stacks per shift
Good boards per shift = gross output x stacker uptime x quality yield

Inputs explained

Boards per stack:
Stacks per shift:
Stacker uptime:
Quality yield:

How to use the result

Use it when planning shift targets, validating a stacker rate against dryer output, or quantifying how much capacity uptime and reject losses are costing you.
It assumes a steady cycle rate and treats uptime and yield as independent multipliers, so it won't capture surge bottlenecks where the dryer or take-off conveyor starves or floods the stacker mid-shift.

Common questions

How do you calculate stacker capacity for a drywall line? Multiply boards per stack by stacks per shift to get gross output, then multiply by stacker uptime and quality yield. With 4 boards/stack, 480 stacks/shift, 90% uptime and 97% yield you get 1,920 gross dropping to 1,676 good boards.
What is the difference between gross and good stacker capacity? Gross capacity (1,920 boards in the example) is the theoretical count if the stacker never stopped and every board passed. Good capacity (1,676) is what survives after 192 boards of uptime loss and 51.8 boards of yield loss.
What is a good stacker uptime for gypsum board? Well-run board lines target 92-96% stacker uptime; the 90% default here already costs 192 boards per shift. Below ~88% the stacker usually becomes the line constraint.
Why does a small yield drop matter on a stacker? Each rejected board is fully loaded with stucco, paper and dryer fuel, so the 3% yield gap costing ~52 boards per shift represents finished product value scrapped, not just lost machine time.
How do I increase good output without speeding up the stacker? Recover uptime and yield first. Closing the 90% uptime to 95% adds roughly 95 boards per shift here, often cheaper than chasing a faster cycle that the dryer can't feed.

Last reviewed 2026-05-12.